Search results for "coordination polymers"
showing 10 items of 54 documents
Guest Induced Strong Cooperative One- and Two-Step Spin Transitions in Highly Porous Iron(II) Hofmann-Type Metal-Organic Frameworks.
2017
[EN] The synthesis, crystal structure, magnetic, calorimetric, and Mo¿ ssbauer studies of a series of new Hofmann-type spin crossover (SCO) metal¿organic frameworks (MOFs) is reported. The new SCO-MOFs arise from self-assembly of FeII, bis(4-pyridyl)butadiyne (bpb), and [Ag(CN)2] ¿ or [MII(CN)4] 2¿ (MII = Ni, Pd). Interpenetration of four identical 3D networks with ¿-Po topology are obtained for {Fe(bpb)[AgI (CN)2]2} due to the length of the rod-like bismonodentate bpb and [Ag(CN)2] ¿ ligands. The four networks are tightly packed and organized in two subsets orthogonally interpenetrated, while the networks in each subset display parallel interpenetration. This nonporous material undergoes a…
Coordination polymer flexibility leads to polymorphism and enables a crystalline solid-vapour reaction: a multi-technique mechanistic study.
2015
Despite an absence of conventional porosity, the 1D coordination polymer [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 ] (1; TMP=tetramethylpyrazine) can absorb small alcohols from the vapour phase, which insert into AgO bonds to yield coordination polymers [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 (ROH)2 ] (1-ROH; R=Me, Et, iPr). The reactions are reversible single-crystal-to-single-crystal transformations. Vapour-solid equilibria have been examined by gas-phase IR spectroscopy (K=5.68(9)×10(-5) (MeOH), 9.5(3)×10(-6) (EtOH), 6.14(5)×10(-5) (iPrOH) at 295 K, 1 bar). Thermal analyses (TGA, DSC) have enabled quantitative comparison of two-step reactions 1-ROH→1→2, in which 2 is the 2D coordination polymer [Ag4 (O2 …
Guidelines to design new spin crossover materials
2010
International audience; This review focuses on new families of spin crossover (SCO) complexes based on polynitrile anions as new anionic ligands or on polyazamacrocycles as neutral macrocyclic ligands. We have shown that the structural and electronic characteristics (original coordination modes and high electronic delocalization) of the polynitrile anions can be tuned by slight chemical modifications such as substitution of functional groups or variation of the negative charge to design new discrete or polymeric SCO systems.In our ongoing work on the design of new molecular systems based on new ligands that can be fine-tuned via chemical modifications, another promising way which has been r…
Stimuli-responsive hybrid materials: breathing in magnetic layered double hydroxides induced by a thermoresponsive molecule
2014
[EN] A hybrid magnetic multilayer material of micrometric size, with highly crystalline hexagonal crystals consisting of CoAl-LDH ferromagnetic layers intercalated with thermoresponsive 4-(4-anilinophenylazo)benzenesulfonate (AO5) molecules diluted (ratio 9 : 1) with a flexible sodium dodecylsulphate (SDS) surfactant has been obtained. The resulting material exhibits thermochromism attributable to the isomerization between the azo (prevalent at room temperature) and the hydrazone (favoured at higher temperatures) tautomers, leading to a thermomechanical response. In fact, these crystals exhibited thermally induced motion triggering remarkable changes in the crystal morphology and volume. In…
m-Carboranylphosphinate as Versatile Building Blocks To Design all Inorganic Coordination Polymers
2017
The first examples of coordination polymers of manganese(II) and a nickel(II) complex with a purely inorganic carboranylphosphinate ligand are reported, together with its exhaustive characterization. X-ray analysis revealed 1D polymeric chains with carboranylphosphinate ligands bridging two manganese(II) centers. The reactivity of polymer 1 with water and Lewis bases has also been studied Thanks to MINECO (CTQ2015-66143-P, CTQ2010-16237 and SEV-2015-0496), Generalitat de Catalunya (2014/SGR/149), and COST CM1302. E.O. who is enrolled in the PhD program of the UAB thanks for FPU grant
Rational Design of Copper(II)-Uracil Nanoprocessed Coordination Polymers to Improve Their Cytotoxic Activity in Biological Media
2021
This work is focused on the rational structural design of two isostructural Cu(II) nano-coordination polymers (NCPs) with uracil-1-acetic acid (UAcOH) (CP1n) and 5-fluorouracil-1-acetic acid (CP2n). Suitable single crystals for ꭕ-ray diffraction studies of CP1 and CP2 were prepared under hydrothermal conditions, enabling their structural determination as 1D-CP ladder-like polymeric structures. The control of the synthetic parameters allows their processability into water colloids based on nanoplates (CP1n and CP2n). These NCPs are stable in water at physiological pHs for long periods. However, interestingly, CP1n is chemically altered in culture media. These transformations provoke the part…
Solvent-tuned ultrasonic synthesis of 2D coordination polymer nanostructures and flakes
2021
Highlights • Combined ultrasound and solvent assisted synthesis of 2D coordination polymers. • Role of interstitial solvent molecules in the delamination of 2D-CPs. • Influence of the sonication time in delamination and nanostructuration processes. • Morphological and supramolecular transformations in 2D-CPs.
Delamination of 2D coordination polymers : the role of solvent and ultrasound
2019
Two novel cadmium-based 2D coordination polymers have been synthesized and characterized. Experimental results evidence that the best delamination processes occurs when weak interactions dominate the cohesion between layers and solvent molecules are occluded within the crystalline network. In this case, the delamination of the crystals occurs spontaneously in water. On top of that, and thanks to the high stability of the resulting (flake) colloidal dispersions, we have completed a detailed study of the sonication assisted delamination impact by: I) comparison of two different sonication approaches (bath vs. tip sonication) and II) optimization of final flake morphology and yield by controll…
Self-Assembly of 1D/2D Hybrid Nanostructures Consisting of a Cd(II) Coordination Polymer and NiAl-Layered Double Hydroxides
2015
The preparation and characterization of a novel hybrid material based on the combination of a 2D-layered double hydroxide (LDH) nanosheets and a 1D-coordination polymer (1D-CP) has been achieved through a simple mixture of suspensions of both building blocks via an exfoliation/restacking approach. The hybrid material has been thoroughly characterized demonstrating that the 1D-CP moieties are intercalated as well as adsorbed on the surface of the LDH, giving rise to a layered assembly with the coexistence of the functionalities of their initial constituents. This hybrid represents the first example of the assembly of 1D/2D nanomaterials combining LDH with CP and opens the door for a plethora…
Direct formation of Sub-Micron and Nanoparticles of a bioinspired coordination polymer based on Copper with Adenine
2017
We report on the use of different reaction conditions, e.g., temperature, time, and/or concentration of reactants, to gain control over the particle formation of a bioinspired coordination polymer based on copper(II) and adenine, allowing homogeneous particle production from microto submicro-, and up to nano-size. Additionally, studies on this reaction carried out in the presence of different surfactants gives rise to the control of the particle size due to the modulation of the electrostatic interactions. Stability of the water suspensions obtained within the time and pH has been evaluated. We have also studied that there is no significant effect of the size reduction in the magnetic prope…